Coral bleaching is the loss ofintracellular endosymbionts through either expulsion or loss of algalpigmentation. The corals that form the structure of the great reef ecosystemsof tropical seas depend upon a symbiotic relationship with algae-likeunicellular flagellate protozoa that are photosynthetic and live within theirtissues.
Monitoring reef sea surface temperature
The US National Oceanic and AtmosphericAdministration (NOAA) monitors for bleaching "hot spots", areas wheresea surface temperature rises 1 °C or more above the long-term monthly average.This system detected the worldwide 1998 bleaching event, that corresponded toan El Niño. NOAA also uses a nighttime-only satellite; these observations aretaken at night to avoid the increase in temperature due to daily warming causedby solar heating at the sea surface during the day. This is also a precautionto avoid glare from the sun.
Changes in ocean chemistry
Increasing ocean acidification due to risesin carbon dioxide levels exacerbates the bleaching effects of thermal stress.Acidification affects the corals' ability to create calcareous skeletons, essentialto their survival. A recent study from the Atkinson Center for a SustainableFuture found that with the combination of acidification and temperature rises,the levels of CO2 could become too high for coral to survive in as little as 50years.
Test Point – TPO27L1
Now, we’ve talked in depth about coralbleaching, or whitening, which as you recall, is a symptom of ...well that thecoral is suffering. As you know, coral is very sensitive to water temperature.Even though one or two degree Celsius rise in sea surface temperature for arelatively short amount of time can cause bleaching. Recently, researchers haveused data collected by monitoring surface water temperatures to improve theability of a reef to recover from bleaching. One future possibility is thatimproved monitoring can help predict where and when bleaching will occur, whichmight potentially enable us to mitigate its effects.
And there’s another technique that’s beenexperimented with to try to help coral reefs recover from bleaching. It’scalled coral transplantation. This involves moving young coral from a healthyreef onto a degraded reef, you know, in an attempt to regenerate the degradedreef by encouraging young healthy coral to take over. There has been some successwith this, but it’s still somewhat controversial. Some scientists support itbecause, well for one thing, it means you don’t have to rely on the existingcoral to reestablish itself because it might not be able to. But in my opinion,transplanting coral should only be used as ... well as a last resort. I mean,this method is not only costly but it’s ... well even if it’s successful, itstill fails to address the ongoing problem, the root causes of the degradation,which really is paramount to devising an effective solution. So I don’t reallytake comfort in the successes they have had with transplantation.